EQ: How can we summarize and compare data? MM1D3a Monday – 8/29/11 Math 1: Unit 1 – Day 5.

EQ: How can we summarize and compare data?

MM1D3a

Monday – 8/29/11

Math 1: Unit 1 – Day 5

The data below represent the grades of students in an “Algebra 1” class:61 44 65 72 57 63 91 6769 79 22 53 54 14 79 33

• Reset your calculator by hitting [on] and [clear] at the same time

• Hit [data] and type the data into list L1• Hit [2nd][data] and choose “1:1-Var Stats”

1) Mean, Median, Q1, Q3, etc

The data below represent the grades of students in an “Algebra 1” class:61 44 65 72 57 63 91 6769 79 22 53 54 14 79 33

Mean ( ): _________ Median (2nd Quartile): ________ Mode: _______

Lower Extreme: ______ Upper Extreme: _______

1st Quartile: _______ 3rd Quartile: _______

x

Video Tutorial

1) Mean, Median, Q1, Q3, etc

57.7 62

14 91

48.5 70.5

79

1009080706050403020

Min Q1

Median

Q2 Q3 Max

2) Mean Absolute Deviation

Find the meanFind the distances from the meanFind the average of the distancesVideo Tutorial

2) Mean Absolute Deviation

Find the meano Hit [data] and type data into L1o Hit [2nd][data] and choose “1:1-Var Stats”o The mean is 58

2) Mean Absolute DeviationFind the distances from the mean of 58o Hit [data] and Arrow over to L2o Hit [data] and arrow to “FORMULA”

o Choose “1:Add/Edit Frmla”o Hit [data] and choose L1 then type “-58” [enter]o Type the absolute values of L2 into L3

2) Mean Absolute DeviationFind the mean of the distances in L3o Hit [2nd][data] and choose “1:1-Var Stats”o Make sure L3 is highlighted

o The average distance from the mean is 15.5o This is the mean absolute deviation

3)

4)

Class 1

90 10080706050403030

•We know the median is 70

•We know the interquartile range is 15

•Here are the possibilities

Class 2

90 10080706050403030

•We know the median is 75

•We know the interquartile range is 12

•Here are the possibilities

Class 1 and Class 2

90 10080706050403030

Class 2

Class 1 Q3 zone

Q3 zone

•We know that both classes had the same 3rd quartile score

•Where is it possible that the 3rd quartile could be the same?

•From where to where do the Q3 zones overlap?

•It looks like 75 to 85

The answer is D.

4)

Calls made during June: 11, 15, 10, 37, 17, 14, 9, 15What is the mean (absolute) deviation for calls made in June?

5)

Calls made during July: 13, 9, 16, 8, 17, 20, 8, 13What is the mean (absolute) deviation for calls made in July?

6)

The mean absolute deviation tells you how variable the data is. A bigger deviation means the data is more spread out.

During which month were the calls more variable?7)

13x 5.3mad

The June calls were more variable based on the higher mean absolute deviation.

16x 5.5mad